The analysis of dust-associated substances represents an important possibility for evaluating pollution situations and exposure concentrations of certain chemical or biogenic substances, especially in indoor areas. Toxic substances, such as pesticides, polyaromatic hydrocarbons or polychlorinated biphenyls, as well as allergy-inducing biogenic substances, such as allergens of dust mites, epithelia of domestic animals or molds are of particular significance.
According to the current state of the art, the detection of dust-associated substances requires, besides an extraction step, the separation of the particles from extractants and a subsequent, usually complicated laboratory analysis.
For example, the polyaromatic hydrocarbon benzopyrene is determined by collection on a glass fiber filter in the total dust in a recognized analytical method for determining cancer-causing working materials. The quantification of benzopyrene is performed by means of a thin-layer chromatographic or gas chromatographic detection following extraction with a solvent and separation of the particulate components.
The drawback of this process is that the individual working steps are carried out separately and the handling involved in the entire analysis is complicated.
Immunochemical detection methods were developed for the detection of some relevant indoor allergens, e.g., those of mites and cats. The dust-associated allergens are eluted with water after separating the particles. The allergen concentration is subsequently determined separately from the eluate by means of the ELISA method ("Enzyme-Linked Immunosorbent Assay").
A process with which dust-associated allergens are detected based on their enzyme activity is described in EP 0 377 229. The underlying process comprises a complicated sample preparation comprising extraction, dialysis and affinity chromatography, before the detection reaction can be carried out.
A process with which the allergen burden caused by dust mites can be quantified on the basis of the detection of the guanine concentration in house dust is described in U.S. Pat. No. 4,806,490. After a complicated sample preparation, comprising a plurality of extraction and centrifuging steps, the guanine content in the house dust is determined according to a separate colorimetric reaction with aromatic diazo compounds.
A simpler process for determining dust-bound macromolecular analytes is described in WO 96/07099. The device on which this process is based makes it possible to elute dust-associated macromolecules, e.g., allergens, from dust particles collected on a filter. The macromolecules are immobilized in the immediate vicinity of the particles. The immobilized macromolecules can subsequently be detected by means of chemical/biochemical solid-phase reactions. The drawback of this process is that the detection reaction must subsequently be performed as a separate step.